1. Field of the Invention
The present invention relates to a pressure switch including a diaphragm.
2. Description of the Related Art
An air-conditioning system or the like generally includes a pressure switch which is provided to piping and configured to detect a pressure of a coolant, carbon dioxide gas, and the like in the piping and to send a detection output. As disclosed in Japanese Patent Laid-Open No. 2002-279875, such a pressure switch includes: a casing assembly connected to a coolant passage via one end of a joint pipe; a diaphragm laminate which partitions off a pressure sensing chamber as a pressure-receiving chamber in the casing assembly; and a rod capable of bringing a movable contact and a fixed contact that are located in the casing assembly close to or away from each other in response to a displacement of the diaphragm laminate. In the above-described configuration, grid-like multipoint contacts are formed on an upper face of the fixed contact which is opposed to the movable contact. Accordingly, if a foreign substance such as a fiber or a contaminant is caught between the fixed contact and the movable contact, the foreign substance is pushed into a recess between the multipoint contacts. Thus, continuity between the fixed contact and the movable contact is secured whereby occurrence of a continuity defect is avoided.
In addition, as disclosed in Japanese Patent Laid-Open No. H10-134681(1998), for example, there is also proposed a pressure switch which is deprived of an actuating force transmission member such as the aforementioned actuating pin and is provided with a curved diaphragm in place of the above-described movable contact. Here, a central part of the curved diaphragm is made invertible so that the diaphragm can come into contact with or move away from a fixed contact. This diaphragm is held by a pressing portion of an insulator member to be fitted into a recess of a body, such that the curved portion of the diaphragm is opposed to the fixed contact.